Zonisamide in the treatment of epilepsy.

IMPORTANCE OF THE FIELD: More than 1 million epilepsy patients suffer from insufficiently controlled epilepsy, both in the USA and in Europe. Zonisamide is an antiepileptic drug with multiple mechanisms of action, corresponding to efficacy in diverse epilepsy syndromes. AREAS COVERED IN THIS REVIEW: Here, an update on pharmacodynamics, pharmacokinetics, clinical efficacy and safety in childhood and adult epilepsies is given based on an analysis of controlled and uncontrolled studies, European, US and East Asian, and on clinical experience with zonisamide (ZNS) published up to 2009. WHAT THE READER WILL GAIN: Evidence is presented that ZNS is effective not only in adult focal epilepsies, for which it has been approved in the USA and in Europe, but also may offer treatment options for compassionate use in a spectrum of difficult-to-treat epilepsy syndromes. Its favorable pharmacokinetic profile allows for easy combination with most available antiepileptic drugs. TAKE HOME MESSAGE: Provided that additional studies on ZNS are performed to extend approval and to generate comparative data, ZNS has a potential to gain importance in the treatmnt of a wide spectrum of epilepsy patients.